Schizophrenia (SZ) is a severe and persistent debilitating psychiatric illness that is generally associated with considerable morbidity and extreme disability. Due to the severity of this disorder, especially the negative impact of a psychotic episode on a patient, and the diminishing recovery after each psychotic episode, there is a need to more conclusively identify individuals who have or are at risk of developing SZ, for example, to confirm clinical diagnoses, to allow for prophylactic therapies, to determine appropriate therapies based on their genotypic subtype, and to provide genetic counseling for prospective parents with a history of the disorder.
Various genes and chromosomes have been implicated in etiology of SZ. Whole genome scans for genes involved in SZ and related SZ-spectrum disorders (including schizotypal personality disorder (SPD) and schizoaffective disorder (SD)) have implicated numerous autosomes as having a role in the genetic etiology of SZ and related SZ-spectrum disorders (Badner et al., Mol. Psychiatry 7:405-411 (2002) Bennett et al., Mol. Psychiatry 7:189-200 (2002) Cooper-Casey et al., Mol. Psychiatry 10:651-656 (2005) Devlin et al., Mol. Psychiatry 7:689-694 (2002) Fallin et al., Am. J. Hum. Genet. 73:601-611 (2003) Ginns et al., Proc. Natl. Acad. Sci. U.S.A 95:15531-15536 (1998) Jablensky, Mol. Psychiatry (2006) Kirov et al., J. Clin. Invest 115:1440-1448 (2005) Norton et al., Curr. Opin. Psychiatry 19:158-164 (2006) Owen et al., Mol. Psychiatry 9:14-27 (2004)). Generally, these linkage scans have are too low in resolution to identify specific genes, but increasingly, transmission disequilibrium (TDT, family-based association) and Case/Control association studies have evaluated a number of positional candidate genes with a good measure of success (Fallin et al., Am. J. Hum. Genet. 77:918-936 (2005)).